Environment maps getting screwy after editing mesh in Blender

[Dandie]

I'm trying to get along with Blender, but it seems that env maps are getting jealous. Sometimes, when I make a simple edit to a mesh, those maps move a small angle. Nothing too extreme, but still makes me sad.
Example: I've tried to remove a cap from empty beer bottle (creating an empty beer bottle mesh by doing so, no less). Everything is good, I succesfully export it and stuff, but env maps start to look wrong, like those rays now are not vertical.

(Edited mesh is on the top image, vanilla, yeah, on the bottom one)
I'm not good with Blender (huh, you bet) etc. So can anyone help me with this issue, please? Good advice is much appreciated.
P.S: also, I noticed that after doing any changes to newly imported mesh, vertex paint (I guess it is vertex paint - those shadows seen in Blender, right?) changed, though rather imperceptibly.

Edited November 26, 2013 by Dandie